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 ###Instrução: Qual é o ano mais baixo, quando a superfície é dura e o oponente é Dinara Safina?
 ###Tabelas: CREATE TABLE national_panhellenic_conference_npc (national_panhellenic_conference_npc_id AUTO_INCREMENT PRIMARY KEY, Letters VARCHAR, Organization VARCHAR, Nickname VARCHAR, Founding Date VARCHAR, Founding University VARCHAR, Type VARCHAR, Canadian Chapters VARCHAR) CREATE TABLE list_of_sponsored_cosponsored_legislation (list_of_sponsored_cosponsored_legislation_id AUTO_INCREMENT PRIMARY KEY, Years covered VARCHAR, All bills sponsored INT, All amendments sponsored INT, All bills cosponsored INT, All amendments cosponsored INT, Original bills cosponsored INT, Original amendments cosponsored INT, Bill support withdrawn INT, Amendment support withdrawn INT) CREATE TABLE singles:_21_17_titles_4_runner-ups (singles:_21_17_titles_4_runner-ups_id AUTO_INCREMENT PRIMARY KEY, Outcome VARCHAR, Year INT, Championship VARCHAR, Surface VARCHAR, Opponent VARCHAR, Score VARCHAR) CREATE TABLE engine_reference (engine_reference_id AUTO_INCREMENT PRIMARY KEY, Code VARCHAR, Vehicle VARCHAR, Year VARCHAR, Displacement VARCHAR, Bore VARCHAR, Stroke VARCHAR, C.R. VARCHAR, Max. Power VARCHAR) CREATE TABLE riders'_jersey_progress_table (riders'_jersey_progress_table_id AUTO_INCREMENT PRIMARY KEY, Stage INT, Winner VARCHAR, General Classification VARCHAR, Mountains Classification VARCHAR, Sprint Classification VARCHAR, Team Classification VARCHAR)  
SELECT MIN Year FROM singles:_21_17_titles_4_runner-ups WHERE Surface = hard AND Opponent = dinara safina